1. Field of the Invention
The present invention relates in general to a susceptor device. In particular, the present invention relates to a susceptor device in a masked sputtering chamber, the application of which increases the life of the mask in the chamber.
2. Description of the Related Art
In a conventional sputtering chamber, it is necessary to prevent residue from being deposited on the inside wall of the chamber. Normally a mask surrounds the space between the substrate and the target in the chamber to prevent film residue from forming on the inside wall of the chamber. After the sputtering process is performed several times, it is necessary to remove the mask from the chamber for preventative maintenance (PM). Unfortunately, sputtering equipment can not be used at this time. Thus, production is dependent upon the timing of PM. As well, cleaning the mask is expensive thus increasing production costs.
In the sputtering process for fabricating liquid crystal display (LCD) units, it is necessary to deposit indium tin oxide (ITO) on the glass substrate, and the described problem occurs when the ITO film forms on the mask. Since the ITO film is usually amorphous, it peels off the mask due to weak adhesion and contamination of the chamber takes place. Thus, it is necessary to remove the mask for frequent PM. The problems of yield and cost previously mentioned are likewise heightened. The conventional method of solving these problems is, when sputtering is not underway, to heat the susceptor by means of a heat coil mounted on the bottom of the susceptor. Thus, a baking process is administered to the ITO film deposited on the mask. As a result, the ITO film is converted to polycrystalline ITO film, increasing its adhesion. These measures do grossly contribute to extending the life of the mask. Unfortunately, the thickness of the susceptor greatly inhibits rapid temperature changes, impacting production by causing lengthy PM sessions, or restricting the frequency of these sessions, thereby curtailing the efficacy of the solution.
An object of the present invention is to provide a susceptor device in a masked sputtering chamber with which the ITO film formed on the mask undergoes a baking process, thereby increasing the life of the mask.
The device of the present invention comprises a susceptor, a lifter and at least one heater. The susceptor has a positioning surface on which the substrate is placed, a supported surface opposite the positioning surface, at least one trench located on the positioning surface, and at least one access hole through the supported surface from the trench, all of which is disposed in the chamber. The lifter has a supporting section to prop up the supported surface and at least one supporting rod, where one end of the rod is driven by the lifter and the other end passes through the access hole moving between a first and second position. The other end of the rod through the access hole is coupled with at least one heater. When the other end of the rod is in the first position, the heater is situated in the trench, accommodating the placement of the substrate on the positioning surface. In the second position, the heater is raised above the trench for the application of the baking process. Use of the susceptor device in accordance with the present invention both enhances the life of the mask and reduces the requirements for production-interruptive PM.